AMPHIBIOUS FISHES.

Press, Volume LV, Issue 9993, 24 March 1898, Page 3

AMPHIBIOUS FISHES.

0. P. Holder, in the Soikktiho American.

Recently, in collecting below the high tide mark on one of the Pacifio coast islands, the writer found beneath almost every ston overturned a little fish, literally out of water and iv no way inconvenienced by the lack of its native clement. In the majority of instances the fishes were cliuging to a stone by a singular sucker formed by the anal fins. They had been left by the retreating water, but had apparently preferred the change and were now for several hours breathing air directly instead of taking it from the water after the manner of fishes in general. This peculiar habit has been observed in the European blenny (Blennins pholis). In specimens kept in an aquarium it was found that they became restless when the tide went oat. The observer now placed a stone in the water, and the little fish at once crawled tipon it and rested there, after the manner of a frog, for over on hour, then returning to its native element. Such fishea arc almost as truly amphibious as the frogs and other animals which appear to be equally at home on land or in the water. The case of the blenny would seem to be remarkable, but there are a number of fishes which are not only able to breathe out of water, bat habitually seek their food on land. The moat interesting examples are found among the Gobies of the tropics. The head in this fish is large, the eyes conspiouou* and protruding, the pectoral fins powerful, resembling legs more than fins, and capable of lifting the fish and enabling it to jump along the sands or muddy shores of certain tropical islands. Two genera are known, Periophthalmus and Boleophthalmus, both equally remarkable for their -amphibious habits. They are particularly fond of a shelless mollusk known as Onchidium, which is often left stranded on the shore, to obtain which the fishes crawl out upon the muddy flats and hop along like frogs. They are so active that it is difficult to catch them. Celonel Nicolas Pike informed the writer that he secured his specimens by shooting them with a shot gun. This was at Mauritius, at Matuku Island. Professor Moseley, the naturalist of the Challenger expedition, found them in great numbers also at Ceylon. They were hopping about on the mud flats beneath the mangrove trees, and Professor Moseley states that when pursued they prepared to escape by taking to the land rather than to the water. At eaoh jump they would clear a foot. Hβ says: " I have chased one at Trincomali Harbour, which skipped along before mc until it reached a rock, where it sat on a ledge out of the water in the sun, and waited till I came up. when it skipped along to another rock. The species at the Fijian Islands is P. Koelreuteri, and it is usually found sitting or resting upon the dry roots of the mangrove trees, perfectly at home out of the waters

The first fish ever observed to leave the water, by a European naturalist, was the now famous climbing perch (Anabas). Daldorf in visiting India heard the story as told by natives, to the effcet that these fishes left their native element and walked overland, using their fins <au limbs, but did not believe it. One day a native came to his camp and offered to take him to a spot where the emigrating fishes could be seen. Following the man through the forest, they finally came to a pool or swamp that was rapidly drying up, and from the mud proceeded a line or procession of fishes, making their way up through the grass by,the aid of their fins, presenting a remarkable spectacle. The fishes were emigrating overland; the water of their pool had dried up, and they were deliberately marching away in search of a locality better'suited to a. water-loving community. Daldorf later saw these fwhes climbing small palms, presumably in seftroh of food, though regarding this there iamuch doubt., In certain parts of India this migratory habit of fishes is so well known that the natives anticipate and repair to the localities with baskets and capture them by hundreds. Mr E. A. Legard states that on the Singalese river also this habit is so well known that all the inolosures in which the Anabas are kept are provided with oovers, to prevent the fishes from climbing out. A little fish (Gobius soporator), oommon on the coast of Texas, is almost equally remark* able. A naturalist, in collecting specimens» placed them in a pail, but was aetoeiehed, inpon returning, to find that the fishes hod all crawled up the eides, and were slowly but surely making their way to the water, *nd were apparently not inconvenienced by the change of element. In Gambia the fish Protopterus has a similar habit. At the first suggestion of the dry season it begins to explore the mud in the bottom of the stream in which it is living, and there forme a burrow in which it spends th& weeks and months with not a drdp of water until five rainy season begins again, and it is released. The natives of Kottiar repair every year to the dry banks of the Vergel River and. dig out certain fishes by hundreds as they woula potatoes. They perform the work with pick and shovel, the fish in its oase being dropped heavily, breaking open, displaying the animal eight or ten inches in length and often as lively as though taken frotn the water. It is evident, that these fishea, which can so readily change their method of life, must in some way differ from their com* panions whioh find water an essential. Aα examination of the fishes shows that they have gills over which water flows and by which air is taken and made to serve itdf peculiar purpose. In other words, they have true gills, but in Periophthalmus ana Boleophthalmus the sill cavity ia muoh)* larger than in many fishes and the gills da not fill it, leaving a space which might be filled with air oi water.

In other fishes which habitually leave thi water, as Anabas already referred to, the gill cavity reaches upward, the mucous membrane forming a complicated foliated labyrinthine structure, so that tiie gills really present more of a surface than those of ordinary fishes, whioh spend all their tima in the water. This labyrinthine structure long ago attracted the attention of naturalietej and it was supposed to be a provision lor the storage of water when the fish was travelling overland; but investigation does nob bear out this idea, and it has been shown that this cavities never contain water and are in no sense reservoirs.' The theory held to-day, ia that the complicated organs are so adapted , that they permit the animal to breath either in the water: or directly from the atmosphere. In other words, the labyrinthine organs are lungs, formed, according to Semper, "by modification of a portion' of the water-breathing gill-cavity; the fishes that have them are therefore to be regarded as amphibious with quite as much reason aa toads and frogs, or even better, since the*} are capable of changing the nature of their respiration—of air, that is, or of water—at will and suddenly, without any interrupt tion; nay, are actually accustomsd so to change it."